The present invention concerns hydrocarbon soluble alkyl lactone oxazolines, their method of preparation, the utility of said lactone oxazolines in hydrocarbon fuel and lubricating systems as highly stable anti-rust agents and/or sludge dispersants.
During the past decade, ashless sludge dispersants have become increasingly important, primarily in improving the performance of lubricants and gasoline in keeping the engine clean of deposits, and permitting extended crankcase oil drain periods. Most commercial ashless dispersants fall into several general categories. In one category, an amine or polyamine is attached to a long chain hydrocarbon polymer, usually polyisobutylene, obtained by the reaction of halogenated olefin polymer with polyamine as in U.S. Pat. Nos. 3,275,554; 3,565,592; 3,565,804. In another category, a polyamine is linked to the polyisobutylene through an acid group, such as a long chain monocarboxylic acid, e.g., see U.S. Pat. No. 3,444,170 or a long chain dicarboxylic acid such as polyisobutenylsuccinic anhydride, by forming amide or imide linkages, such as described in U.S. Pat. Nos. 3,172,892; 3,219,666; etc. In still another category the amines and polyamines are linked to the polyalkyl chain through a dicarboxylic acid lactone such as described in U.S. Pat. Nos. 3,200,075; 3,261,782; 3,897,350; 3,936,472, etc.
U.S. Pat. No. 3,261,782 teaches that alkylbutyrolactone-.alpha. acetic acids themselves are useful rust inhibitors in lubricating oil compositions which acids are derived from long chain dicarboxylic acids.
Reaction products of hydrocarbon substituted succinic anhydride, e.g., the aforesaid polyisobutenylsuccinic anhydride, with compounds containing both an amine group and a hydroxy group have been suggested or investigated in the prior art. For example, U.S. Pat. No. 3,272,746 teaches the reaction of ethanolamine and diethanolamine, as well as various hydroxyalkyl substituted alkylene amines, such as N-(2-hydroxyethyl) ethylene diamine, N,N'-bis(2-hydroxyethyl) ethylene diamine, with alkenyl succinic anhydride to obtain ashless dispersants for lube oil. A hydroxy amine, such as diethanolamine, is reacted with a long chain alkenylsuccinic anhydride in U.S. Pat. No. 3,324,033 to form a mixture of esters and amides, wherein some of the diethanolamine reacts through a hydroxy group to give an ester linkage, while another portion of the diethanolamine forms an amide linkage.
United Kingdom Specification No. 809,001 teaches corrosion inhibitors comprising a multiple salt complex derived from the reaction product of hydrocarbyl substituted dicarboxylic acids and hydroxy amines (including 2-amino-2-methyl-1,3-propanediol [AMPD]) and tris-hydroxymethylaminomethane (THAM) further complexed with mono- and polycarboxylic acids (see Examples 17-19).
U.S. Pat. No. 3,576,743 teaches reacting polyisobutenylsuccinic anhydride with a polyol, such as pentaerythritol, followed by reaction with THAM, (see Example 1). U.S. Pat. No. 3,632,511 teaches reacting polyisobutenylsuccinic anhydride with both a polyamine and a polyhydric alcohol including THAM. U.S. Pat. No. 3,697,428 (Example 11) teaches reacting polyisobutenylsuccinic anhydride with a mixture of pentaerythritol and THAM. United Kingdom Specification No. 984,409 teaches ashless, amide/imide/ester type lubricant additives prepared by reacting an alkenyl succinic anhydride, said alkenyl group having 30 to 700 carbon atoms, with a hydroxy amine including THAM.
DOS No. 2512202 teaches reacting long chain hydrocarbon substituted succinic anhydride with 2,2'-disubstituted-2-amino-1-alkanol to produce mono- and bis-oxazoline products (see also DOS No. 2534921/2 for similar reaction products which can also be modified by reaction with phosphorus, boron or oxygen compounds).
The earlier referenced category of dicarboxylic acid lactone type products have also been provided with anti-rust and/or dispersant properties by reaction with hydroxy amines such as ethanolamine and diethanolamine (see U.S. Pat. Nos. 3,248,187 and 3,620,977).